I have a program that simulates dice rolls and compares them to values in a chart (set of String lists). I currently get the value from a TEdit. If the box is empty it raises a EConvertError that should be caught by my Try/Except statement, but it's not. Thoughts and advice? Code below, Delphi 7.
try
//Shooting
if ShootingRadio.Checked then
BS := StrToInt(Edit1.Text);
Randomize;
Roll := RandomRange(1,7);
Label3.Caption := IntToStr(Roll);
if (Roll < StrToInt(ShootingHitChart[BS-1])) then
begin
Label3.Caption := (IntToStr(Roll)+' Miss');
RichView1.AddTextNL((IntToStr(Roll)+' Miss'),7,0,1);
RichView1.Reformat;
end
else
begin
Label3.Caption := (IntToStr(Roll)+' Hit');
RichView1.AddTextNL((IntToStr(Roll)+' Hit'),6,0,1);
RichView1.Reformat;
end;
except
MessageBox(0,'No number entered.','Error',mb_OK);
end;
'Stop on Delphi exceptions' is checked in the debugger options. The exception is actually caught just fine, but the IDE stops when you get it. When you continue running, you will not see the exception, but your message instead. Out of the IDE it will run fine.
You can uncheck this option (I usually do). You can always re-check it when you need to debug some stubborn problem.
Related
I'm trying to capture the debugger notification text, Firedac connection
//FDScript1.SQLScripts.Add.SQL.LoadFromFile('C:\SGI\Rodar_Apos_Atualizar_3.txt');
//FDScript1.ValidateAll;
//FDScript1.ExecuteAll;
//MSScript1.SQL.LoadFromFile('C:\SGI\Rodar_Apos_Atualizar_3.txt');
//MSScript1.Execute;
try
FDConnection1.Connected := True;
FDScript1.SQLScripts.Add.SQL.LoadFromFile('C:\SGI\Rodar_Apos_Atualizar_3.txt');
FDScript1.ExecuteAll;
FDScript1.ValidateAll;
except
//EMSSQLNativeException
on E: EMSSQLNativeException do
begin
//ShowMessage('Erro'+FDGUIxErrorDialog1.ErrorDialog.Caption);
//Memo1.Clear;
Memo1.Text := 'Erro de Sistema: '+#13#10+ E.Message;
end;
end;
It really would help if you would show us the scripts you are trying to execute,
or at least the script which does not execute correctly. In any case, your code is wrong
because the documentation
states
It is good practice to call the ValidateAll method before the ExecuteAll method.
Note the 'before'. Your ValidateAll is after ExecuteAll, not before. Both are Boolean
functions but you are not checking their results, which you should.
With some trivial experimenting I found that I can provoke a EMSSQLNativeException
using SqlServer 2014 with the code below:
procedure TForm2.Button1Click(Sender: TObject);
const
sScript = 'select m.*, d.* from master m join detail d on, m.masterid = d.masterid';
var
FDScript : TFDSqlScript;
begin
try
FDConnection1.Connected := True;
FDScript := FDScript1.SQLScripts.Add;
FDScript.SQL.Text := sScript;
//FDScript1.ExecuteAll;
//FDScript1.ValidateAll;
// FDScript1.ValidateAll then
//FDScript1.ExecuteAll;
FDQuery1.SQL.Text := sScript;
FDQuery1.Open();
except
//EMSSQLNativeException
on E: EMSSQLNativeException do
begin
//ShowMessage('Erro'+FDGUIxErrorDialog1.ErrorDialog.Caption);
//Memo1.Clear;
Memo1.Text := 'Erro de Sistema: '+#13#10+ E.Message;
end;
end;
end;
Note the blatantly wrong syntax in the Sql statement, namely the comma after the on.
When FDQuery1.Open is called, this exception is raised (and caught initially by the debugger)
---------------------------
Debugger Exception Notification
---------------------------
Project sqlerror.exe raised exception class EMSSQLNativeException with message '[FireDAC][Phys][ODBC][Microsoft][SQL Server Native Client 11.0][SQL Server]Incorrect syntax near 'd'.'.
---------------------------
Break Continue Help
---------------------------
When I click Continue, execution proceeds into your exception handler, exactly as #TomBrunberg described in a comment
and the exception's message text is inserted into Memo1.
So I cannot reproduce the behaviour you describe based on the information in your question. It
must be caused by something you are not telling us, possibly in code you have
not included in your q or some property setting of the components you are
using.
Hopefully, trying the code above, you will find the debugger behaving as I
have described and this may give you some clue as to why you are getting the
problem you've described. Note that it is very important that you try the code
above in a new project, not your existing one. The only property setting
you need to do before executing it is to set FDConnection1 so that it can connect
to your server.
FWIW, if I uncomment-out the lines
FDScript1.ValidateAll then
FDScript1.ExecuteAll;
they execute without complaint, and I get the exact same behaviour as i've described without them.
I have a nasty error when executing a Firedac TFDScript error trying to drop a non-existent table:
Delphi Berlin 10.1 Upd 2
Database Firebird 2.5
It give an error when calling FDScript.ExecuteAll (it passes the FDScript.ValidateAll without any problem)
The code I am executing is as follows:
FDScript: TFDScript;
{...}
begin
FDScript.ScriptOptions.Reset;
FDScript.SQLScripts.Clear;
FDScript.SQLScriptFileName := '';
FDScript.ScriptOptions.CommandSeparator := ';';
FDScript.ScriptOptions.CommitEachNCommands := 1;
FDScript.ScriptOptions.DropNonexistObj := True; // seems to ignore this directive
FDConnection.StartTransaction;
try
FDScript.SQLScripts.Add.SQL.Add('drop table countries;');
FDScript.ValidateAll; // no errors here
ScriptStatus := GetEnumName(TypeInfo(TFDScriptStatus), Ord(FDScript.Status));
if FDScript.Status = ssFinishSuccess then begin
FDScript.ExecuteAll; // ERROR HERE! TABLE COUNTRIES DOES NOT EXIXTS
if FDScript.TotalErrors = 0 then begin
FDConnection.Commit;
end
else begin
FDConnection.Rollback;
end;
end
else begin
FDConnection.Rollback;
end;
except
FDConnection.Rollback;
raise;
end;
end;
Implementation seems to be correct. The engine checks if a raised exception is of ekObjNotExists kind, and if so and the DropNonexistObj property is enabled and command kind is DROP or ALTER, it logs to its console. Otherwise re-raises the caught exception.
The only explanation is then, that you are seeing an exception message dialog shown by debugger. These dialogs are displayed even for handled exceptions (so long you won't add them to an ignore list or turn this feature off, which you should not do).
I have this method where i execute a sql statement and catch a error in a try except statement
AdoQuery := TAdoQuery.Create(self);
AdoQuery.connection := AdoConnection;
AdoQuery.SQL.Add(sqlStr);
AdoQuery.Prepared := true;
try
begin
AdoQuery.ExecSql;
AdoQuery.Active := false;
end;
except on e:eAdoError do
ShowMessage('Error while creating the table: ' + e.Message);
end;
I can catch the error like this and show it to the user but it's showing some useless info for the user. I Would like to show only the %msg part of the error, take a look at the pic:
I tought e.MEssage allow me to get only the %msg part but it give me the whole thing hardly understoodable by a random user. How do i get only the usefull info in this case
Table reftabtest.rPCE already exists
Thank you.
You can use the Errors property of the TADOConnection object, what you want is the Description member of the Error object.
In your case:
function ParseOBDCError(ErrorDescription : String) : String;
var
Ps : Integer;
Pattern : String;
begin
Pattern := '%msg:';
Ps := Pos(Pattern, ErrorDescription);
if Ps > 0 then
begin
Result := Copy(ErrorDescription, Ps+Length(Pattern)+1);
// if you want, you can clean out other parts like < and >
Result := StringReplace(Result, '<', , '', [rfReplaceAll]);
Result := StringReplace(Result, '>', , '', [rfReplaceAll]);
Result := Trim(Result);
end
else
Result := ErrorDescription;
end;
...
AdoQuery := TAdoQuery.Create(self);
AdoQuery.connection := AdoConnection;
AdoQuery.SQL.Add(sqlStr);
AdoQuery.Prepared := true;
try
AdoQuery.ExecSql;
AdoQuery.Active := false;
except on e : Exception do
begin
if AdoConnection.Errors.Count > 0 then
ShowMessageFmt('Error while creating the table: %s',
[ParseOBDCError(AdoConnection.Errors[0].Description)])
else
ShowMessageFmt('something went wrong here: %s', [e.Message]);
end;
end;
That message dialog wasn't shown by your ShowMessage() code.
First, the icon is wrong - that's not the ShowMessage icon.
Second, the text you added ('Error while creating the table: ') to the message is missing.
This means your exception swallower is not catching the exception, because it's not of the EADOError class. So what's happening is the application's default exception handler is showing the exception.
Before I explain how to fix it, I need to point out that your exception swallower is wrong (your's should not be misnamed an exception handler).
Because you're swallowing the exception: If another method calls yours it will incorrectly think you method succeeded, and possibly do something it shouldn't. You should never write code that makes an assumption that there isn't a significant call stack leading into your method.
Swallowing to show a message to the user doesn't help, because it hides the error from the rest of the program. Especially since, as you can see: there is already code in one place that tells the user about the error without hiding it from the rest of the program. (The problem you have is that you want a friendlier message.)
To fix it:
First find out what the actual exception class is, so you're able to catch the correct error.
Now you have a number of options, but the simplest is as follows:
First log the exception, preferably with call stack. You don't want to be stuck in the situation where the user gets a friendly message but you as developer lose critical information if you need to do some debugging.
To get the call stack you can consider third-party tools like Mad Except, Exceptional Magic, JCLDebug to name a few.
Now show the message to the user.
Finally call Abort. This raises an EAbort exception which by convention is a "silent exception". It tells the rest of the program that there was an error (so it doesn't do things assuming everything is fine). But by convention, any further exception handlers should not show another message to the user. This includes the default handler's dialog in your question.
If the default handler is incorrectly showing EAbort messages, then it should be fixed.
We have a program made in Borland Delphi that uses Word automation to create documents.
On an installation (terminal server) we are only able to get the Word automation to work when running as local administrator.
When runnnig as anoter user we get an error message "Opdracht mislukt -2146824090" (its dutch version of Office), wich I guess is translated to "Operation failed" or "Command failed".
The user has read/write access to the folder where the program try to put the new document.
Office 2010
64bits Windows server 2008 R2 standard
The applicaion is 32bit windows application.
If I add a delay (500ms) after the word.application is created, everything works as normall.
WordApp := CreateOleObject('Word.Application');
sleep(500);
Doc := WordApp.documents.Open(sFile,EmptyParam,true);
Anybody knows why the CreateOleObject command now returns before the Word application can be used?
If you want to track out that, you could use a tool like ProcessMonitor to trace the Word automation executions till the point which you can use the app.
Seems some kind of rights check is taking place - but half a second seems too much time just for this.
You could try to open the Document a few times, or is Word totally borked after it gave the error?
WordApp := CreateOleObject('Word.Application');
while True do
begin
try
Doc := WordApp.documents.Open(sFile,EmptyParam,true);
Break;
except
on E: EOleSysError do
begin
// raise error if it's not the expected "Command failed" error
if E.ErrorCode <> -2146824090 then
raise;
end;
end;
end;
Edit:
Please see my answer here which provides a better solution and an explanation why this happens.
The administrator account working wihtout delay, seems not to have anything with rights to do, but that Word happens to start much faster with this account than the normal domain user accounts.
I can live with the delay workaround, but if anyone knows a better way please let me know.
I realize this thread is quite old, but I solved this issue by making sure to close the document before quitting (oleDocument.Close). By doing so there is no need for any type of delays, etc. See Delphi code snippet below.
Example:
oleWord := Unassigned;
oleDocument := Unassigned;
Screen.Cursor := crHourGlass;
try
oleWord := CreateOleObject('Word.Application');
oleWord.Visible := False;
oleWord.DisplayAlerts := False;
oleDocument := oleWord.Documents.Open(Worklist.Filename);
oleDocument.SaveAs(Worklist.Filename, wdFormatDOSTextLineBreaks);
oleDocument.Close;
oleWord.Quit(False);
finally
oleDocument := Unassigned;
oleWord := Unassigned;
Screen.Cursor := crDefault;
end;
Using the DelphiTwain files from http://delphitwain.sourceforge.net/ and am getting some weird behavior.
After each scan a little more memory is being held onto.
After an hour or so of repetitive scans, the image scanned is zoomed in approxamately 10 times, and just the upper-left square inch is stored.
Has anyone had similar issues, or have some suggestions?
Code below...
try
try
Twain := TDelphiTwain.Create(self);
Twain.OnTwainAcquire := TwainAcquireHandler; //manually set the event handler
Twain.OnSourceFileTransfer := TwainSourceFileTransfer;
Twain.OnSourceSetupFileXfer := TwainSourceSetupFileXfer;
Twain.LoadLibrary;
Twain.LoadSourceManager;
Twain.Source[0].Loaded := TRUE;
Twain.Source[0].TransferMode := ttmFile;
Twain.Source[0].EnableSource(false, false);
except on e : exception do
showmessage('Error loading Scanner.');
end;
try
while Twain.Source[0].Enabled do
Application.ProcessMessages;
except on e : exception do
showmessage('Error Scanning Packing List.');
end;
finally
Twain.Source[0].Loaded := FALSE;
Twain.UnloadSourceManager(true);
Twain.UnloadLibrary;
Twain.Destroy;
end;
Since the TDelphiTwain appears to be a component you are creating in code, I would recommend passing in nil for the constructor and calling the .Free method or (as suggested by Joseph) FreeAndNil.
Twain := TDelphiTwain.Create(nil);
try
try
Twain.OnTwainAcquire := TwainAcquireHandler; //manually set the event handler
Twain.OnSourceFileTransfer := TwainSourceFileTransfer;
Twain.OnSourceSetupFileXfer := TwainSourceSetupFileXfer;
Twain.LoadLibrary();
Twain.LoadSourceManager();
Twain.Source[0].Loaded := True;
Twain.Source[0].TransferMode := ttmFile;
Twain.Source[0].EnableSource(False, False);
except on e : exception do
showmessage('Error loading Scanner.');
end;
try
while Twain.Source[0].Enabled do
Application.ProcessMessages;
except on e : exception do
showmessage('Error Scanning Packing List.');
end;
Twain.Source[0].Loaded := False;
Twain.UnloadSourceManager(True);
Twain.UnloadLibrary();
finally
FreeAndNil(Twain);
end;
I would also recommend better exception handling, but not related to question you asked. The only thing users will see and report to you (or worse, the quiet guy in the corner responsible for your IT support who loves to get non-descriptive errors from users) is 'Error doing something'
Good luck
Another area to look at is if the scanner supports WIA (Windows Image Acquisition)
var
DevMgr: IDeviceManager;
Scanner: Idevice;
Picture: IItem;
Image: OleVariant;
AImage: IImageFile;
begin
DevMgr := CreateOleObject('WIA.DeviceManager') as IDeviceManager;
// Figure out which device is the scanner
Scanner:= DevMgr.DeviceInfos.Item[1].Connect;
//Command: Figure out which command scans..
Picture := Scanner.ExecuteCommand(Scanner.Commands.Item[1].CommandID);
//Transfer as JPG
Image := Picture.Transfer(Picture.Formats.Item[1]);
//Save the image
AImage := IImageFile(Image);
AImage.SaveFile('c:\wia_viaScanner\image.' + AImage.FileExtension);
end;
More info on the WIA library can be found here..
http://msdn.microsoft.com/en-us/library/ms629859(VS.85).aspx
Examining the code within these calls may be fruitful:
TwainAcquireHandler;
TwainSourceFileTransfer;
TwainSourceSetupFileXfer;
Do any of those create any objects without freeing them?
If you are using Delphi 2006 or higher, then you can add this line to your .DPR file:
ReportMemoryLeaksOnShutdown := True;
Then reproduce the memory leak, close your app... and it will describe the leaks in detail. A little more info about this can be found here.
On another note, I'd suggest replacing
Twain.Destroy;
with
FreeAndNil(Twain);
.Destroy will call the destructor directly, while FreeAndNil is a safer alternative that will also prevent the "Twain" variable from pointing anywhere dangerous. (See the accepted answer to this question).
I can't address the problem you're reporting but you have a busy loop there that will gobble CPU time.
What are you doing when you get the Image, did you keep in memory?
Or the library can have some memory leaks, you can check if it is true with FastMM4.
to KevinRF:
I need to use WIA automation in Delphi 7 project. I registered WIAAut.dll in my system, import this library into Delphi and past your programm code into my project and got some errors:
Scanner:= DevMgr.DeviceInfos.Item[1].Connect;
Types of actual and formal var parameters must be identical
in "Item" must be Item[var Index: OleVariant], but "1" is integer
What's wrong, what i need to made it works?